Week 2 Day 6

We start off the week with the tricky task of trying to
make our sensors fit on the board in the correct way. As you can see the dust sensor( the large silver unit up top) is rather large, making it difficult to fit neatly on the board.   Its  a bit like doing a jigsaw puzzle with electronic components. We have also added the VOC sensor, which  is the circular silver sensor with small holes in the top.  


The dust sensor will do exactly what its name suggests, detect dust in the air.  It does this by picking up the reflected light from dust in the air.  It is so effective that it can differentiate house dust from cigarette smoke by the pulse pattern of the output voltage.  


The VOC sensor, which stands for Volatile Organic Compounds, has a high sensitivity to low concentrations of odorous gases.  Many VOC's themselves are not hazardous, but play an important role in the formation of ozone.  Ozone is a photo-chemical oxidant  that is generally harmful to plant tissue and human respiratory tissue if found in the troposphere.   

Our first set of sensors is completed!  We attached the dust sensor and VOC sensor to the ARDUINO board ( thats the blue board underneath the red board) which is then connected to the computer via USB.  LabVIEW then converts the readings into ppb.    We have started taking our first measurements, set to log data every 5 minutes.  We are starting with VOC and then will move on to the dust sensor.  The gray wolf unit is currently set up in the same room as our prototype so we can compare the data to make sure it is in a respectable range. 

 After checking our values we found that we had a slight issue with our prototype, but the wire has been reconnected and our output values are coming in well within an acceptable range.  For example, the gray wolf unit is reading 119 ppb and our prototype is reading 117 ppb, close enough for our purposes.

We will leave the units running overnight to get some more data, and then change the locations tomorrow to see if we can get some different readings.  Last thing for today is to get everything ready for our next set of sensors, the temperature/relative humidity and carbon monoxide.  Temperature is in white on the left, and CO is red and circular on the right.  Here it is below...